You can use whatever variety of apple you have on hand!
Sweet apples tend to get sweeter when dehydrated and sour apples tend to get more sour.
My favorite apples to use are Honeycrisp, Granny Smith, or Cosmic Crisp.
After 1 hour, flip apple chips over to prevent sticking.
Flip again around the 2 hour mark.
After 2 hours, the apples should be dry enough that they won't stick, so you'll no longer need to flip them..